Anomalous hydrogen absorption on non-stoichiometric iron-carbon compound

Miyaoka Hiroki

Ichikawa Takayuki

Fujii Tatsuo

Ishida Wataru

Isobe Shigehito

Fuji Hironobu

Kojima Yoshitsugu

Journal of Alloys and Compounds

On the synthesis of nano-structural hydrogenated graphite by ball-milling under H-2 atmosphere, iron contamination was mingled from steel balls during ball-milling. It is clarified by spectroscopic measurements that the mingled iron formed a non-stoichiometric iron-carbon (Fe-C) compound. The Fe-C phase was transformed to a well-ordered phase with H-2 desorption at 450 degrees C, suggesting that the hydrogen atoms were anomalously trapped at the Fe-C phase. With respect to hydrogen absorbing properties, the mingled iron enhanced the hydrogen capacity by about 50% compared with iron free hydrogenated graphite, where H/Fe was about 13 mass%. Therefore, if the hydrogen absorption site originated in the Fe-C phase could be synthesized independently, it should be recognized as a promising hydrogen storage system.

Hydrogen absorbing materials

Amorphous materials

Mechanochemical processing

Mossbauer spectroscopy

X-ray and gamma-ray spectroscopies

Thermal analysis

Chemistry [ 430 ]

eng

Elsevier Science SA

Copyright (c) 2010 Elsevier B.V.

[ISSN] 0925-8388

[DOI] 10.1016/j.jallcom.2010.07.221

[NCID] AA10817249

[DOI] http://dx.doi.org/10.1016/j.jallcom.2010.07.221